Important: Use custom search function to get better results from our thousands of pages

Use " " for compulsory search eg:"electronics seminar" , use -" " for filter something eg: "electronics seminar" -"/tag/" (used for exclude results from tag pages)

Tags: satelli, satellite communication tutorial, satellite communication basics, satellite communication notes, satellite communication in india, satellite communication syllabus, satellite communications, satellite communications ppt, satellite communications by dennis roddy, satellite communications basics, satellite communications jobs, satellite communications answers, satellite communications by timothy pratt, satellite communications dennis roddy, satellite communications pdf, satellite communications tutorial,
Ask More Info Of  A Seminar Ask More Info Of A Project Post Reply  Follow us on Twitter
29-05-2010, 10:48 PM
Post: #1
satellite communication pdf report

.pdf  Avancements in Satellite Communication.pdf (Size: 61.79 KB / Downloads: 1033)

Presented By:
E.C.E (II/IV).


Satellites have evolutionized communication. Satellite communication has served mankind in many ways for instance its is used to predict weather and broadcast storm warnings and also provides a wide range of communication services in the fields of relaying television programs, digital data for a multitude of business services. It might not surprise us if, in near future satellite links are used for voice and fax transmission to aircraft on international routes. Communications satellite systems have entered a period of transition from point-to-point high-capacity trunk communications between large, costly ground terminals to multipoint-to-multipoint communications between small, low-cost stations. As any invention develops with the passage of time, satellite communication has also moved a step ahead from what it was in the past with the use of several techniques such as frequency reuse, interconnecting many ground stations spread over the world, concept of multiple spot beam communications, these days lasers are effectively used for transmission through satellites. The latest development in satellites is the use of networks of small satellites in low earth orbits.

In this present era, communication plays a vital role. We use a wide range of devices to communicate between two persons placed at different places (irrespective of the distance between them). Any earth-orbiting spacecraft that provides communication over long distances by reflecting or relaying radio-frequency signals. Satellites have evolutionized communication by making worldwide telephone links and live broadcasts common occurrences. A satellite receives a microwave signal from a ground station on the earth (the uplink), then amplifies and retransmits the signal back to a receiving station or stations on earth at a different frequency (the downlink). A communication satellite is in geosynchronous orbit, which means that it is orbiting at the same speed as the earth is revolving. The satellite stays in the same position relative to the surface of the earth, so that the broadcasting station will never lose contact with the receiver.


Some of the first communications satellites were designed to operate in a passive mode. Instead of actively transmitting radio signals, they served merely to reflect signals that were beamed up to them by transmitting stations on the ground. Signals were reflected in all directions, so receiving stations around the world could pick them up. Echo 1, launched by the United States in 1960, consisted of an aluminized plastic balloon 30 m (100 ft) in diameter. Launched in 1964, Echo 2 was 41 m (135 ft) in diameter. The capacity of such systems was severely limited by the need for powerful transmitters and large ground antennas.
Score, launched by the United States in 1958, was the first active communications satellite. It was equipped with a tape recorder that stored messages received while passing over a transmitting ground station. These messages were retransmitted when the satellite passed over a receiving station. Telstar 1, launched by American Telephone and Telegraph Company in 1962, provided direct television transmission between the United States, Europe, and Japan and could also relay several hundred-voice channels. Launched into an elliptical orbit inclined 45° to the equatorial plane, Telstar could only relay signals between two ground stations for a short period during each revolution, when both stations were in its line of sight.
Hundreds of active communications satellites are now in orbit. They receive signals from one ground station, amplify them, and then retransmit them at a different frequency to another station. Satellites use ranges of different frequencies, measured in hertz (Hz) or cycles per second, for receiving and transmitting signals. Many satellites use a band of frequencies of about 6 billion hertz, or 6 gigahertz (GHz) for upward, or uplink, transmission and 4 GHZ for downward, or downlink, transmission. Another band at 14 GHZ (uplink) and 11 or 12 GHZ (downlink) is also much in use, mostly with fixed (nonmobile) ground stations. A band at about 1.5 GHZ (for both uplink and downlink) is used with small, mobile ground stations (ships, land vehicles, and aircraft). Solar energy cells mounted on large panels attached to the satellite provide power for reception and transmission.


A satellite in a geosynchronous orbit follows a circular orbit over the equator at an altitude of 35,800 km (22,300 mi), completing one orbit every 24 hours, in the time that it takes the earth to rotate once. Moving in the same direction as the earth's rotation, the satellite remains in a fixed position over a point on the equator, thereby providing uninterrupted contact between ground stations in its line of sight. The first communications satellite to be placed in this type of orbit was Syncom 2, launched by the National Aeronautics and Space Administration (NASA) in 1963. Most communications satellites that followed were also placed in geosynchronous orbit.


Deployment and operation of communications satellites on a commercial basis began with the founding of the Communications Satellite Corporation (COMSAT) in 1963. When the International Telecommunications Satellite Organization
(INTELSAT) was formed in 1964, COMSAT became the U.S. member. Based in
Washington, D.C., INTELSAT is owned by more than 120 nations. Intelsat 1, known as Early Bird, launched in 1965, provided either 240 voice circuits or one two-way television channel between the United States and Europe. During the 1960s and 1970s, message capacity and transmission power of the Intelsat 2, 3, and 4 generations were progressively increased.
The first of the Intelsat 4s, launched in 1971, provided 4,000 voice circuits. With the Intelsat 5 series (1980), innovations in signal focusing resulted in additional increases in capacity. A satellite's power could now be concentrated on small regions of the earth, making possible smaller-aperture, lower-cost ground stations. An Intelsat 5 satellite can typically carry 12,000 voice circits. The Intelsat 6 satellites, which entered service in 1989, can carry 24,000 circuits and feature dynamic on-board switching of telephone capacity among six beams, using a technique called SS-TDMA (satellite-switched time division multiple access). In the early 2000s, INTELSAT had 21 satellites in orbit, providing the world's most extensive telecommunications system. Other systems also provide international service in competition with INTELSAT. The growth of international systems has been paralleled by domestic and regional systems, such as the U.S. Telstar, Galaxy, and Spacenet programs and Europe's Eutelsat and Telecom.

Broadcasters use data from meteorological satellites to predict weather and to broadcast storm warnings when necessary. Satellites such as the Geostationary Operational Environmental Satellite (GOES) collect meteorological and infrared information about the atmosphere and the ocean. A camera on the GOES is continuously pointed at Earth, broadcasting satellite images of cloud patterns both day and night. Here, the GOES-C satellite is being encapsulated inside its payload fairing aboard a Delta rocket.

Commercial satellites provide a wide range of communications services. Television programs are relayed internationally, giving rise to the phenomenon known as the "global village." Satellites also relay programs to cable television systems as well as to homes equipped with dish antennas. In addition, very small aperture terminals (VSATs) relay digital data for a multitude of business services. Intelsat satellites now carry over 100,000 telephone circuits, with growing use of digital transmission. Digital source coding methods have resulted in a ten-fold reduction in the transmission rate needed to carry a voice channel, thus enhancing the capacity of existing facilities and reducing the size of ground stations that provide telephone service.

Weather satellites carry cameras and other instruments pointed toward Earth's atmosphere. They can provide advance warning of severe weather and are a great aid to weather forecasting. NASA launched the first weather satellite, Television Infrared Observation Satellite (TIROS) 1, in 1960. TIROS 1 transmitted almost 23,000 photographs of Earth and its atmosphere. NASA operates the Geostationary Operational Environmental Satellite (GOES) series, which are in geostationary orbit. GOES provides information for weather forecasting, including the tracking of storms. Meteosat 3, a European weather satellite also in geostationary orbit, augments GOES. The National Oceanic and Atmospheric Administration (NOAA) operate three satellites that collect data for long-term weather forecasting.

The International Mobile Satellite Organization (INMARSAT), founded in 1979 as the International Maritime Satellite Organization, is a mobile telecommunications network, providing digital data links, telephone, and facsimile transmission, or fax, service between ships, offshore facilities, and shore-based stations throughout the world. It is also now extending satellite links for voice and fax transmission to aircraft on international routes.


Launched on October 4, 1957, the Sputnik 1 was the first craft in Earth's orbit. Named after the Russian word for "traveling companion of the world" (Sputnik Zemli), it was a small satellite measuring only 58 cm (23 in) across. It circled the earth once every 96.2 minutes and transmitted atmospheric information by radio. After three months aloft, it was destroyed while reentering the atmosphere.
Communications satellite systems have entered a period of transition from point-to-point high-capacity trunk communications between large, costly ground terminals to multipoint-to-multipoint communications between small, low-cost stations. The development of multiple access methods has both hastened and facilitated this transition. With TDMA, each ground station is assigned a time slot on the same channel for use in transmitting its communications; all other stations monitor these slots and select the communications directed to them. By amplifying a single carrier frequency in each satellite repeater, TDMA ensures the most efficient use of the satellite's onboard power supply.

A technique called frequency reuse allows satellites to communicate with a number of ground stations using the same frequency by transmitting in narrow beams pointed toward each of the stations. Beam widths can be adjusted to cover areas as large as the entire United States or as small as a state like Maryland. Two stations far enough apart can receive different messages transmitted on the same frequency. Satellite antennas have been designed to transmit several beams in different directions, using the same reflector.
A method for interconnecting many ground stations spread over great distances was demonstrated in 1993 with the launch of NASA's ACTS (Advanced Communications Technology Satellite). The satellite uses what is known as the hopping spot beam technique to combine the advantages of frequency reuse, spot beams, and TDMA. By concentrating the energy of the satellite's transmitted signal, ACTS can use ground stations that have smaller antennas and reduced power requirements.
The concept of multiple spot beam communications was successfully demonstrated in 1991 with the launch of Italsat, developed by the Italian Research Council. With six spot beams operating at 30 GHZ (uplink) and 20 GHZ (downlink), the satellite interconnects TDMA transmissions between ground stations in all the major economic centers of Italy. It does this by demodulating uplink signals, routing them between up- and downlink beams, and combining and remodulating them for downlink transmission.
Laser beams can also be used to transmit signals between a satellite and the earth, but the rate of transmission is limited because of absorption and scattering by the atmosphere. Lasers operating in the blue-green wavelength, which penetrates water, have been used for communication between satellites and submarines.

The latest development in satellites is the use of networks of small satellites in low earth orbit (2,000 km (1,200 mi) or less) to provide global telephone communication. The Iridium system uses 66 satellites in low earth orbit, while other groups have or are developing similar systems. Special telephones that communicate with these satellites allow users to access the regular telephone network and place calls from anywhere on the globe. Anticipated customers of these systems include international business travelers and people living or working in remote areas.

Looking at the rate of advancement in satellite communication one would foresee the use of satellites in every field where communication is required such as relaying television and radio signals. Special telephones that communicate with these satellites allow users to access the regular telephone network and place calls from anywhere on the globe.



> Communication satellites
> Wireless communications
> Artificial satellites
> Space exploration.


> Satellite Communications by Timothy Pratt and Dennis Roddy.
> Satellite Communication Systems by M. Richharia.
> Satellite communication systems by Gerard Maral, Michel Bousquet

read more

Please Use Search wisely To Get More Information About A Seminar Or Project Topic
30-05-2010, 09:37 PM
Post: #2
RE: satellite communication pdf report

Please Use Search wisely To Get More Information About A Seminar Or Project Topic
17-06-2010, 01:40 PM
Post: #3
RE: satellite communication pdf report

.docx  satellite communications.docx (Size: 604.04 KB / Downloads: 306)



What is a satellite
Can we imitate nature(artificial satellites)
Types of satellites.
Why satellites for communication
Low earth-orbiting communication satellites.
Geosynchronous communication satellite.
Basic communication satellite components
How satellites are used today.
New satellite communications.
The note book computer :the latest in satellite gear.
Direct broadcast: Satellite T.V.
Satellite advances in television.
Future global satellite network.
Some of the launch vehicles used to send satellites into space.
Conclusion & Bibliography.


The main theme involved in developing this paper is to provide a clear understanding of
satellites,pupose of satellites and their types, need of satellite communications in day-to-day
life. there are two types of communication satellites low earth orbit communication satellites
(LEO) and geosynchronous communication satellites. under LEO communication satellites there
comes Echo and Telstar communication satellites, their advantages and disadvantages and
advancements of geosynchronous communication satellites compared to LEOâ„¢s has been
discussed. A brief idea on basic communication satellite components has been given.
In the years to come, there are many projected plans in the area of satellites. This will be
a benefit to the United States and the rest of the world. Some of these advances are in satellite
photography, communications, and weather technology. Some of the future advances are in the
distant future, while others are being developed right now. The usage of satellites today, new
satellite communications, the latest in satellite gear, direct broadcast satellite T.V, satellite
advances in television, future global satellite networks. we have also presented some of the
launch vehicles used to send satellites into space.

What is a Satellite

A satellite is something that goes around and around a larger something, like the earth or
another planet. Some satellites are natural, like the moon, which is a natural satellite of the earth.
Other satellites are made by scientists and technologists to go around the earth and do certain
Can We Imitate Nature (Artificial Satellites)
Very soon after Newton's laws were published, people realized that in principle it should
be possible to launch an artificial satellite which would orbit the earth just as the moon does. A
simple calculation, however, using the equations which we developed above, will show that an
artificial satellite, orbiting near the surface of the earth (R = 4000 miles) will have a period of
approximately 90 minutes. This corresponds to a sideways velocity (needed in order to "miss"
the earth as it falls), of approximately 17,000 miles/hour (that's about 5 miles/second).

Types Of Satellites

Boeing 376, built by Boeing Satellite Systems. The Boeing 376 is used mostly for
broadcast television and cable television.
Boeing 601”which is also built by Boeing Satellite Systems. The Boeing 601 is used for
many purposes, including direct broadcast TV, such as DIRECTV. Direct broadcast TV is a
system for receiving television using a very small satellite dish. The television signal is relayed
by a Boeing 601 satellite. The Boeing 601 also relays telephone, fax, and computer
The most powerful commercial satellite in the world is the Boeing 702. Designed and
built by Boeing Satellite Systems, this giant has a wingspan of nearly 157 feet”more than a
Boeing 757 jet plane.

Why Satellites for Communications

By the end of World War II, the world had had a taste of "global communications."
Edward R. Murrow's radio broadcasts from London had electrified American listeners. We had,
of course, been able to do transatlantic telephone calls and telegraph via underwater cables for
almost 50 years. At exactly this time, however, a new phenomenon was born. The first television
programs were being broadcast, but the greater amount of information required to transmit
television pictures required that they operate at much higher frequencies than radio stations.
Television signals, however required much higher frequencies because they were transmitting
much more information - namely the picture. Both radio and television frequency signals can
propagate directly from transmitter to receiver. This is a very dependable signal, but it is more or
less limited to line of sight communication. T0he mode of propagation employed for long
distance (1000s of miles) radio communication was a signal which traveled by bouncing off the
charged layers of the atmosphere (ionosphere) and returning to earth. The higher frequency
television signals did not bounce off the ionosphere and as a result disappeared into space in a
relatively short distance. This is shown in the diagram below.
Radio Signals Reflect Off the Ionosphere; TV Signals Do Not
In addition, of course, the appetite for transatlantic radio and telephone was increasing
rapidly. Adding this increase to the demands of the new television medium, existing
communications capabilities were simply not able to handle all of the requirements. By the late
1950s the newly developed artificial satellites seemed to offer the potential for satisfying many
of these needs.
Low Earth-Orbiting Communications Satellites
In 1960, the simplest communications satellite ever conceived was launched. It was
called Echo, because it consisted only of a large (100 feet in diameter) aluminized plastic
balloon. Radio and TV signals transmitted to the satellite would be reflected back to earth and
could be received by any station within view of the satellite.

Echo Satellite

Unfortunately, in its low earth orbit, the Echo satellite circled the earth every ninety
minutes. This meant that although virtually everybody on earth would eventually see it, no one
person, ever saw it for more than 10 minutes or so out of every 90 minute orbit. In 1958, the
Score satellite had been put into orbit. It carried a tape recorder which would record messages as
it passed over an originating station and then rebroadcast them as it passed over the destination.
Once more, however, it appeared only briefly every 90 minutes - a serious impediment to real
communications. In 1962, NASA launched the Telstar satellite for AT&T.

Telstar Communications Satellite

Telstar's orbit was such that it could "see" Europe" and the US simultaneously during one
part of its orbit. During another part of its orbit it could see both Japan and the U.S. As a result, it
provided real- time communications between the United States and those two areas - for a few
minutes out of every hour.
Geosynchronous Communications Satellites:
The solution to the problem of availability, of course, lay in the use of the geosynchronous orbit.
In 1963, the necessary rocket booster power was available for the first time and the first
geosynchronous satellite , Syncom 2, was launched by NASA. For those who could "see" it, the
satellite was available 100% of the time, 24 hours a day. The satellite could view approximately
42% of the earth. For those outside of that viewing area, of course, the satellite was NEVER

Syncom II Communications Satellite

However, a system of three such satellites, with the ability to relay messages from one to the
other could interconnect virtually all of the earth except the polar regions. The one disadvantage
(for some purposes) of the geosynchronous orbit is that the time to transmit a signal from earth
to the satellite and back is approximately ¼ of a second - the time required to travel 22,000 miles
up and 22,000 miles back down at the speed of light. For telephone conversations, this delay can
sometimes be annoying. For data transmission and most other uses it is not significant. In any
event, once Syncom had demonstrated the technology necessary to launch a geosynchronous
satellite, a virtual explosion of such satellites followed.
Today, there are approximately 150 communications satellites in orbit, with over 100 in
geosynchronous orbit. One of the biggest sponsors of satellite development was Intelsat, an
internationally-owned corporation which has launched 8 different series of satellites (4 or 5 of
each series) over a period of more than 30 years. Spreading their satellites around the globe and
making provision to relay from one satellite to another, they made it possible to transmit 1000s
of phone calls between almost any two points on the earth. It was also possible for the first time,
due to the large capacity of the satellites, to transmit live television pictures between virtually
any two points on earth. By 1964 (if you could stay up late enough), you could for the first time
watch the Olympic games live from Tokyo. A few years later of course you could watch the
Vietnam war live on the evening news.
Basic Communications Satellite Components
Every communications satellite in its simplest form (whether low earth or
geosynchronous) involves the transmission of information from an originating ground station to
the satellite (the uplink), followed by a retransmission of the information from the satellite back
to the ground (the downlink). The downlink may either be to a select number of ground stations
or it may be broadcast to everyone in a large area. Hence the satellite must have a receiver and a
receive antenna, a transmitter and a transmit antenna, some method for connecting the uplink to
the downlink for retransmission, and prime electrical power to run all of the electronics. The
exact nature of these components will differ, depending on the orbit and the system architecture,
but every communications satellite must have these basic components. This is illustrated in the
following drawing.
Basic Components of a Communications Satellite Link

How Satellites are Used Today

Today Satellites are used for direct broadcast television, wireless cable, cellular telephone,
photography, and video tele-conferencing. The special sports programs, movies, and news
broadcasts are all televised because of satellites. Artificial satellites have been launched to
photograph the moon, Mars, Venus, Saturn, and Jupiter. Other satellites send information, back
to the Earth about the weather of the Earth.
Planet 1: New Satellite Communications
A new satellite system is known as Planet 1. It integrates cellular and satellite technology to
provide mobile voice, data, and facsimile communications. "The package weighs less than six
pounds and the price is $2,995, plus a $3 a minute in use charges." (Miller, 134) By the end of
the year, it is expected that Planet 1 service will be offered to countries all around the world.
The Notebook Computer: The Latest in Satellite Gear
Now the business traveler can go anywhere on business without having to worry whether they
can make their business call.
New technology has put the out of touch traveler in touch with the world. Recent advances in
satellite technology have provided the use of compact cellular phones. "Travelers can take along
the latest in satellite gear, which is no bigger than a notebook computer."(Miller,134)
Direct Broadcast: Satellite TV
Direct Broadcast Satellite television is a very costly business. Wireless cable technology brings
pay TV to rural areas. This technology works by beaming signals from a central tower to dishes
on the roofs of houses or buildings. The new technology is cheaper than laying wires under the
Satellite Advances in Television
Special satellites send pictures and messages from one continent to another . Dish antennas are
used to send and receive information. A television show that is broadcasted live from one
country can also be seen in another country which is half way around the world. Communication
services are now using small antennas to send and receive the information.
Future Global Satellite Network
AT&T Corp. has filed an application to build and launch a global satellite network. This would
allow computer users to bypass telephone networks and connect directly to the internet by
satellite. "AT&T has used satellites in its international long distance network." (Ley,32) This
new technology would involve a network of satellites positioned around the Earth.
Some of the launch vehicles used to send satellites into space


Additional satellites are scheduled for launch that will enable new communication
systems to be used around the world. Advances in the new Satellite Technology have made
people no more than a phone call away. Satellites can send messages from one continent to
another and also from one planet to another. Satellite technology brings us the weather, cellular
phones, wireless cable, and direct broadcast television. Satellite communication companies are
expecting these services to be offered all over the world in the very near future.


Please Use Search wisely To Get More Information About A Seminar Or Project Topic
18-08-2010, 07:23 PM
Post: #4
RE: satellite communication pdf report
Undecided ok i mhfhsrtnvcgxg
19-02-2011, 10:01 AM
Post: #5
RE: satellite communication pdf report

.doc  Satelite communication.doc (Size: 36.5 KB / Downloads: 123)
In today’s communication plays very important role in all walks of life. The demands of communication have increase to such extent that a new word “Personal Communication has appeared on the scene”.When we talk to personal communication on a global basis we say that the communication satellite is a very simple concept which sometimes change the world. The credit of invention of modern satellite goes to the British scientist and fiction writer ARTHUR C. CLARK communication satellite is radio relay in the sky. Signals are send to its from antenna on the earth, it amplifies the signals and sends them back. Three satellite cover almost all the inhabited region of the earth. Satellite communication technology has proved to be the most advanced means of communication. Satellite can provide the capability of simultaneous transmission of many television voice and data channels. For economical effort the satellite expert arrived for conclusion that using non-Geo system economically viable.They considered three types of orbits, name low earth orbit ie LEO medium earth orbit or bit ie MEO and high elliptically earth orbit ie HEO.
Satellite are not stationary. They revolves around earth in certain orbit typical path of an orbiting satellite areEquatorialPolarInclinedThe orbit it self may be elliptical or circular. But satellite is mostly said to be two types according to its orbit and speed
.a. Geostationary Satellite
If the satellite orbits in an equatorial plane at exactly the same angular velocity as the earth rotates it will appear to be fixed at a specific point in the sky when viewed from the earth. Such a satellite is said to be Geo synchronous or geo-stationary satellite. For synchronous orbit to occur three times of orbiting satellite to complete one revolution must be equal to hours 56 minutes and 4 seconds. This will occur at an altitude of 35784 Km. For Geo-stationary satellites points on earth beyond about 80 altitude are not visible byt they require simple earth station, no tracking is required.
b. Inclined satellites
These satellite are other than Geo-stationary satellites but can provide visibility to the higher nor them as well as southern latitude.For inclined satellite earth stations have to continuously track satellite for the communication.SATELLITE SYSTEMSThere are three types of satellites systems
In this type or system an unlink ground based earth station to satellites and down link back to ground takes places that is communication between two remote earth station visible to the same satellites takes place.
This system consist of a satellite cross link between two satellites prior to down link transmission. Such system allow communication between earth station not visible to the same satellite. By spacing multiple satellite in proper orbit around the earth worldwide communication between remote earth station in different hemispheres can be performed via such cross link.
Ground-User relay
This systems is a satellite relay system involving earth station, near earth users like air craft, ship, cars etc. and satellites. An earth station communication to another earth station or to a near earth user by transmitting to relay satellite will have larger near earth visibility than the transmission earth station. A relay satellite allows communication to a wider range of users. The user responds by retranslating back through the satellite to the earth station.The link from earth station to relay to user is called forward link, while link from user to satellite back to the earth is called return link. 3. FUNDAMENTALS OF SATELLITE COMMUNICATIONA satellite communications systems basically consists of a satellite in space and many earth station on the ground which are linked with each other through the satellite. The components involved in satellite communication are ground segment equipment, free space and space segment.
Ground segment equipment
Ground segment equipment is basically a digital earth station whose functional block diagram is given in figure.The digital signal through the terrestrial network inters the base band equipment where it is processed like buffered, multiplexed, formatted etc. Error correction error rate to an acceptable level. There a buster it is modulated using intermediate frequency ie IF carrier to 70 mHz, a standard frequency in satellite communication for a communication channel using 36 MHz transpoder. The modulated a carrier is further modulated to a satellite uplink radio frequency ie RF carrier and is sent to HPA for transmission to satellite. Similarly, on the received by low noise amplifies which amplifiesit, keeping carrier-to-noise ration at an acceptable level to meet the error rate equipment. The down converter translates it to the IF level which is red to the demodulators where the digital steam at data is extracted. Personal earth station/micro earth station or central hub station are ground segment equipment working on the same basic principle.Free spaceFree space is the medium between the satellite and earth satellite station which others certain obstruction for RF in both the uplink and the down link paths. The transmitted received signals undergo energy loss as they pass though the free space, termed as free space less. This can be measured in terms of dB.
Free space loss dB = 32.4 + 20 log ‘d’ + 20 log f
Where,d – Maximum slant range in km f – up link of carrier frequency
25-03-2011, 10:23 AM
Post: #6
RE: satellite communication pdf report
Presented by:

.ppt  satellite.ppt (Size: 312.5 KB / Downloads: 113)
Satellite Communications
 Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means.
 The two stations can use a satellite as a relay station for their communication
 One Earth Station sends a transmission to the satellite. This is called a Uplink.
 The satellite Transponder converts the signal and sends it down to the second earth station. This is called a Downlink.
Basics: Advantages of Satellites
 The advantages of satellite communication over terrestrial communication are:
 The coverage area of a satellite greatly exceeds that of a terrestrial system.
 Transmission cost of a satellite is independent of the distance from the center of the coverage area.
 Satellite to Satellite communication is very precise.
 Higher Bandwidths are available for use.
Basics: Disadvantages of Satellites
 The disadvantages of satellite communication:
 Launching satellites into orbit is costly.
 Satellite bandwidth is gradually becoming used up.
 There is a larger propagation delay in satellite communication than in terrestrial communication.
Basics: How Satellites are used
 Service Types
 Fixed Service Satellites (FSS)
• Example: Point to Point Communication
 Broadcast Service Satellites (BSS)
• Example: Satellite Television/Radio
• Also called Direct Broadcast Service (DBS).
 Mobile Service Satellites (MSS)
• Example: Satellite Phones
Types of Satellites
Satellite Orbits

 Molniya Orbit
 HAPs
 Frequency Bands
Geostationary Earth Orbit (GEO)
 These satellites are in orbit 35,863 km above the earth’s surface along the equator.
 Objects in Geostationary orbit revolve around the earth at the same speed as the earth rotates. This means GEO satellites remain in the same position relative to the surface of earth.
 Advantages
 A GEO satellite’s distance from earth gives it a large coverage area, almost a fourth of the earth’s surface.
 GEO satellites have a 24 hour view of a particular area.
 These factors make it ideal for satellite broadcast and other multipoint applications.
 Disadvantages
 A GEO satellite’s distance also cause it to have both a comparatively weak signal and a time delay in the signal, which is bad for point to point communication.
 GEO satellites, centered above the equator, have difficulty broadcasting signals to near polar regions
Low Earth Orbit (LEO)
 LEO satellites are much closer to the earth than GEO satellites, ranging from 500 to 1,500 km above the surface.
 LEO satellites don’t stay in fixed position relative to the surface, and are only visible for 15 to 20 minutes each pass.
 A network of LEO satellites is necessary for LEO satellites to be useful
 Advantages
 A LEO satellite’s proximity to earth compared to a GEO satellite gives it a better signal strength and less of a time delay, which makes it better for point to point communication.
 A LEO satellite’s smaller area of coverage is less of a waste of bandwidth.
 Disadvantages
 A network of LEO satellites is needed, which can be costly
 LEO satellites have to compensate for Doppler shifts cause by their relative movement.
 Atmospheric drag effects LEO satellites, causing gradual orbital deterioration.
Medium Earth Orbit (MEO)
 A MEO satellite is in orbit somewhere between 8,000 km and 18,000 km above the earth’s surface.
 MEO satellites are similar to LEO satellites in functionality.
 MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 to 8 hours.
 MEO satellites have a larger coverage area than LEO satellites.
 Advantage
 A MEO satellite’s longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network.
 Disadvantage
 A MEO satellite’s distance gives it a longer time delay and weaker signal than a LEO satellite, though not as bad as a GEO satellite.
Other Orbits
 Molniya Orbit Satellites
 Used by Russia for decades.
 Molniya Orbit is an elliptical orbit. The satellite remains in a nearly fixed position relative to earth for eight hours.
 A series of three Molniya satellites can act like a GEO satellite.
 Useful in near polar regions.
High Altitude Platform (HAP)
 One of the newest ideas in satellite communication.
 A blimp or plane around 20 km above the earth’s surface is used as a satellite.
 HAPs would have very small coverage area, but would have a comparatively strong signal.
 Cheaper to put in position, but would require a lot of them in a network.
Capacity Allocation
 Advantages over FDMA
 Satellite frequency is already broken into bands, and is broken in to smaller channels in Frequency Division Multiple Access (FDMA).
 Overall bandwidth within a frequency band is increased due to frequency reuse (a frequency is used by two carriers with orthogonal polarization).
 The number of sub-channels is limited by three factors:
 Thermal noise (too weak a signal will be effected by background noise).
 Intermodulation noise (too strong a signal will cause noise).
 Crosstalk (cause by excessive frequency reusing).
 FDMA can be performed in two ways:
 Fixed-assignment multiple access (FAMA): The sub-channel assignments are of a fixed allotment. Ideal for broadcast satellite communication.
 Demand-assignment multiple access (DAMA): The sub-channel allotment changes based on demand. Ideal for point to point communication.
 TDMA (Time Division Multiple Access) breaks a transmission into multiple time slots, each one dedicated to a different transmitter.
 TDMA is increasingly becoming more widespread in satellite communication.
 TDMA uses the same techniques (FAMA and DAMA) as FDMA does.
Advantages of TDMA over FDMA.
 Digital equipment used in time division multiplexing is increasingly becoming cheaper.
 There are advantages in digital transmission techniques. Ex: error correction.
 Lack of intermodulation noise means increased efficiency.
28-01-2012, 12:30 PM
Post: #7
RE: satellite communication pdf report
satellite communication

.docx  New Microsoft Office Word Document.docx (Size: 262.68 KB / Downloads: 39)
See: Geostationary Orbit and Geosynchronous orbit Satellites.
The first artificial satellite was the Soviet Sputnik 1, launched on October 4, 1957, and equipped with an on-board radio-transmitter that worked on two frequencies, 20.005 and 40.002 MHz. The first American satellite to relay communications was Project SCORE in 1958, which used a tape recorder to store and forward voice messages. It was used to send a Christmas greeting to the world from U.S. President Dwight D. Eisenhower. NASA launched an Echo satellite in 1960; the 100-foot (30 m) aluminized PET film balloon served as a passive reflector for radio

Molniya satellites
Main article: Molniya orbit
Geostationary satellites must operate above the equator and will therefore appear lower on the horizon as the receiver gets the farther from the equator. This will cause problems for extreme northerly latitudes, affecting connectivity and causing multipath (interference caused by signals reflecting off the ground and into the ground antenna). For areas close to the North (and South) Pole, a geostationary satellite may appear below the horizon. Therefore Molniya orbit satellite have been launched, mainly in Russia, to alleviate this problem.

Satellite Applications

The first and historically most important application for communication satellites was in intercontinental long distance telephony. The fixed Public Switched Telephone Network relays telephone calls from land line telephones to an earth station, where they are then transmitted to a geostationary satellite. The downlink follows an analogous path. Improvements in submarine communications cables, through the use of fiber-optics, caused some decline in the use of satellites for fixed telephony in the late 20th century, but they still serve remote islands such as Ascension Island, Saint Helena, Diego Garcia, and Easter Island, where no submarine cables are in service. There are also regions of some continents and countries where landline

Fixed Service Satellite

Fixed Service Satellites use the C band, and the lower portions of the Ku bands. They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, live shots, and backhauls), as well as being used for distance learning by schools and universities, business television (BTV), Videoconferencing, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends.
15-02-2012, 02:56 PM
Post: #8
RE: satellite communication pdf report
to get information about the topic future satellite communication full report ,ppt and related topic refer the link bellow









Rating satellite communication pdf report Options
Share satellite communication pdf report To Your Friends :- Seminar Topics Bookmark
Post Reply 

Marked Categories : satellite, ppt on satellite communication geostationary orbit, satellite communication ppt by dennis roddy, latest launch satellite communication ppt, satellite communication, download link satellite communication system m richharia, pdf of satellite communication by roody, satellite communication system of usa pdf, mode de transmission par satellite pdf, satellite communication technology pdf, on pdf, sattillitecommunication document, satellite communication system, satellite communication tutorial pdf, report on satellite communication, satellite communication tutorial ppt, satelight pdf, topic satellite telecommunications, satellites communication pdf,

Quick Reply
Type your reply to this message here.

Image Verification
Image Verification
(case insensitive)
Please enter the text within the image on the left in to the text box below. This process is used to prevent automated posts.

Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Invisible Eye- Advanced Security System report project girl 2 3,314 31-08-2016 01:12 PM
Last Post: jaseela123
  INTELLECTUAL CAMERA UNIT pdf project girl 2 1,388 02-08-2016 02:52 PM
Last Post: dhanabhagya
  ARM PROCESSOR full report computer science technology 17 18,702 19-07-2016 12:10 PM
Last Post: jaseela123
  blue brain project full report seminar topics 58 50,958 18-07-2016 02:16 PM
Last Post: jaseela123
  Satellite Radio presentation Abstract 2 507 09-05-2016 02:31 PM
Last Post: mkaasees
  5G MOBILE TECHNOLOGY SEMINAR REPORT seminar code 1 1,066 09-04-2016 10:40 AM
Last Post: mkaasees
  Wireless Power Transmission via Solar Power Satellite full report project topics 42 64,748 07-04-2016 03:09 PM
Last Post: dhanabhagya
  A Seminar Report On E-TEXTILES project girl 1 1,416 05-04-2016 10:46 AM
Last Post: mkaasees
  electrodynamic tether full report project reporter 5 11,857 31-03-2016 12:55 PM
Last Post: mkaasees
  universal current sensor full report project report tiger 17 17,877 31-03-2016 09:52 AM
Last Post: mkaasees
This Page May Contain What is satellite communication pdf report And Latest Information/News About satellite communication pdf report,If Not ...Use Search to get more info about satellite communication pdf report Or Ask Here